


I've Got New Rules, I Count 'Em

by thefaerielights



Category: Life with Derek
Genre: Banter, Because it's Casey and Derek, F/M, Fluff and Humor, Home Alone, Sharing a Bed, Thunderstorms, Unintentional Snuggling, cursing
Language: English
Status: Completed
Published: 2018-01-01
Updated: 2018-01-01
Packaged: 2019-02-26 03:40:03
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,230
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13227342
Author URL: https://archiveofourown.org/users/thefaerielights/pseuds/thefaerielights
Summary: Nora and George obviously weren't thinking when they left Casey and Derek home alone one night. Luckily for them, a thunderstorm keeps the two of them from killing each other - and leads to the two of them sharing a bed one dark and stormy night.





	I've Got New Rules, I Count 'Em

**Author's Note:**

> **Disclaimer** : Obviously, I don't own Life With Derek - if I did, it would have lasted a lot longer and we would still be watching Casey and Derek banter, fight, and fall in love. Also, if there are any typos, feel free to yell at me - maybe then I'll finally start proofreading my own work.

George and Nora were normally quite smart, competent parents – so it was really a mystery why they thought it was a good idea to leave Casey and Derek alone in their house without locking them in separate rooms. Really, the only smart thing they did was take their remaining children with them, which would hopefully keep them safe from any destruction that was sure to happen.

To be fair, it wasn’t really their choice – it was the darn summer camp where Lizzie and Edwin were going to that was to blame. It was too far away for them to drive up in one day, drop the two off, and come back, so they decided to make a little day trip out of the thing and stop at a hotel on their way. The family dinner where this announcement was made led to immediate complaining.

“Mom! George! Emily and I were going to go to the movies that night and then come back here. We’ve been making plans all week and talking about it – there’s no way I can just un-invite her now. That would be so inconsiderate!” Casey said, leaning toward her mother as if proximity could change Nora’s mind.

“There’s a hockey game on that night that I wanted to watch, and you know that I hate sharing a bed with Ed – unless you two are going to spring for my own hotel room, it’s just going to be terrible. You might only have one kid to drop off the next time,” Derek shot back, grasping his brother in a harsh grip that could _maybe_ be called a hug.

George sighed. “So, what, we’re supposed to just leave you two behind, all by yourself? That sounds like a great way to need a new home when we get back.”

“George, how could you assume that I would be a problem like Derek? You know that I would keep the house in perfect shape – I could even tidy the living room up a little without everyone running around and getting in my way.”

“Hey! I’m a wonderful distraction!” Edwin said with a smirk as he put way too much lasagna in his mouth. “And what’s wrong with the living room – we live in it, and it looks like that, that’s the whole point.”

Casey rolled her eyes before looking back at her mom. “Come on, Mom, you know you can trust me. If I didn’t come along, you could get one hotel room with two big beds and a couch and not have to worry about getting a second room – it’d be much cheaper!”

“And what about Derek? Would he be stuck on the couch?” George asked.

Casey grit her teeth and sighed before answering. “Derek could stay here, too. Mom and Lizzie could share a bed, George and Marti could have the other one, and Edwin could take the couch.”

“The floor works as well,” Derek said with his default smirk. Edwin glared at him.

Nora looked at George. “Well, what do you think? It’s just the one night.”

George sighed. “We’re going to regret this.”

“Oh, you’re definitely going to regret this,” Lizzie said.

By the time Saturday rolled around, the day that they were leaving, they were still regretting it, but they knew that it would be even more of a headache if they changed their minds and tried to bring Casey and Derek along. Besides, the two of them stuck alone in the same house was a bit better than being stuck in the same car – at least, it would be better for the other people in the car.

“Don’t worry, Mom, you can totally trust me. As soon as the movie is over, Emily and I will come back and make sure that Derek doesn’t do anything stupid.”

“Excuse me, I think you mean exciting and interesting,” Derek said with a smirk and an arm slung around Casey’s shoulders.

“You would think those words were all synonyms,” Casey shot back.

“Oh, look at that, George, we really need to get out of here,” Nora quickly said. “Good bye, sweetie, I’ll call you when we get to the hotel.”

She kissed Casey on the cheek and gave Derek a look before gathering up the rest of the kids. George gave Derek a look as well, but he turned it to Casey as well.

“If this house is destroyed when we get back, you two will be buying us a new house,” he said before following Nora.

Casey rolled her eyes and shoved Derek’s arm off. “I’ll be in my room until I leave – _don’t_ bother me.”

“Well, gosh darn, there goes my plans for the day,” Derek said with an eye roll of his own before heading over to his chair. He fell back in it with plenty of creaking – Casey really wished they could just get rid of the damn thing already.

The rest of the day passed quietly for once. Casey spent the hours straightening up her already fairly clean bedroom, reading a particularly good book, and doing some calming yoga – she had a feeling that Derek would find a way to irritate her and Emily that night. She didn’t hear anything from him, though, other than the vague sounds of the TV, so maybe he was starting to mature in his grand old age of seventeen.

It wasn’t a thought that Casey would bet good money on, though.

Casey was so enthralled by her book that she didn’t notice the way the sky had gotten darker and low rumbling could occasionally be heard. She hadn’t bothered checking the weather earlier because it wasn’t like she was going to be spending time outside or in the car with her family – if she had, she would have seen the predictions for heavy rain and bad thunderstorms.

She didn’t notice the weather at all until she heard her phone ringing and saw that it was Emily.

“Casey, I’m _so sorry_ , but my parents won’t let me come out tonight. They’re worried about the weather.”

“What weather?” Casey asked, a split second before a deafening strike of lightning blasted outside of her window. She jumped and nearly dropped the phone. “Oh, that weather.”

“We’ll have to reschedule for another night. My parents don’t even want me to come over to your house when it’s pouring so horribly.”

Casey sighed. “I understand, but what am I supposed to do now? I’m stuck alone in the house with Derek!”

“I don’t know – hang out with him?”

“Emily!”

“Sorry, I don’t know what I was thinking. I don’t know, Casey, but I need to go – my window is open and the rain is really coming in and getting everything wet. Talk to you later, okay?”

“Yeah, don’t worry about me,” Casey said, but she didn’t do a good job of masking her disappointment. She fell back on her bed with a loud sigh.

Now what?

She finally decided that Derek had monopolized the living room and TV long enough. She headed downstairs, armed with a blanket and her comfiest pajamas. If she wasn’t going to go out with Emily, she might as well be comfortable. It wasn’t like she was trying to impress Derek of all people.

As suspected, Derek was still watching TV – he probably hadn’t even moved from his chair since she had gone upstairs. It was a wonder that anyone at school found him impressive. If they shared a house with him, they would change their mind immediately.

“My turn,” Casey said as she grabbed the remote, which he had been loosely holding. In fact, Casey had a feeling that he was seconds away from falling asleep before she had spoken – oh well, it served him right, refusing to go on the trip with the others. She could have had the whole house to herself.

“Hey, I was watching that!” Derek grunted, although it was hard to take him seriously when he looked like he was coming out of a bad hangover or a particularly draining hockey practice. He made a half-hearted swipe in Casey’s direction, but considering she was settling into the opposite side of the couch at that exact moment, he really wasn’t doing a good job of retrieving the remote. It was a bit sad to watch, really, although Casey knew she would cherish this moment later.

“Quick quiz – what were you watching just now?” Casey asked with a smug look on her face. “If you can tell me that, I’ll give you the remote back.”

Derek blearily looked over at the TV, but Casey had already changed it to a new channel, so it wasn’t much help. “Um, hockey?”

“Bzzz, sorry sir, but that’s incorrect. You have lost the game,” Casey said into the remote, looking a lot more satisfied than she really should be. If Derek were in better form, he could have wiped that expression off her face, but he was still trying to wake up.

Casey turned to the TV and began flipping through the channels, trying to find a movie or a show that was easy to jump into. She was distracted, and after years of living with Derek, she really should have known better, but she was still feeling triumphant, and so that was her excuse for letting her guard down.

“Der-ek!” Casey shrieked when Derek was suddenly leaping from the chair onto the couch and basically crushing her in the process. His name was a bit muffled since her head was currently somewhere under an elbow or a knee or possibly Derek’s whole torso. “Get off me!”

“Give me the remote!” Derek shot back, his hands suddenly everywhere in his attempt to find the remote. Of course, in the tussle that he had initiated, the remote had disappeared.

Casey kept trying to block his hands, but she was also trying to find the remote before he did, so she was half-blocking, half-searching. She was still half under Derek as well, so her arms were only able to move so far before she found them trapped again.

Someone must have found it with their knee or some other part of their bodies that weren’t their hands and suddenly the volume of the TV was quickly increasing. They had landed on some sort of children’s show, so they were suddenly bombarded with some perky song sung by high-pitched children.

“Der-ek, this is all your fault,” Casey managed to grunt out in between her continued search and an attempt to elbow Derek in the gut.

If Casey was thinking clearly, she would have known that a handsy Derek could easily turn into a gropey Derek, whether he meant to or not.

“Der-EK! THAT IS NOT THE REMOTE!” Casey roared.

Derek suddenly stopped moving and looked down at one of his hands, which was in fact not holding the remote, but seemed to be cupping one of Casey’s breasts. His eyes got wide and his face white, but he wasn’t moving.

The hand was still there. The hand was still on her freaking tit and Casey was not handling it well.

“Der-ek!” Casey herself had been motionless in her anger, but now she finally pushed Derek back. He was apparently so in shock that he fell all the way to the floor, red flooding into his face. Casey started to think about blood rushing other places and now she was the one blushing like mad.

Why the hell hadn’t her mother and George just shoved Derek into the trunk and made him sleep in there? Why, oh why, did they let him stay there alone with her?

Derek still wasn’t moving. Casey leaned over the edge of the couch to look at him. “Are you okay?”

He finally shook out of whatever stupor he had fallen into. “Um, I think I’m going to go upstairs, upstairs to my room, and I think I am just going to stay there.”

The TV was still blasting at them about two feet away, so Casey could barely hear him.

“What?”

“I’m outta here,” Derek said as he pulled himself to his feet and practically ran to the stairs. He almost tripped halfway up the stairs, barely catching himself on the railing without missing a step.

Casey looked at the now-empty stairs in shock. What the hell had just happened?

It took a few minutes for Casey to break out of her own stupor, probably because another song had come on whatever show was currently screaming at her and she was starting to get a headache. She finally found the remote, which had burrowed its way under her butt (she took a moment to thank every deity possible that Derek wasn’t still there, still looking for the remote in its final resting place), and she turned down the volume before returning to her search of a good show.

But she wasn’t really paying that much attention. At least 60% of her brain was upstairs with a certain irritating brother.

Stepbrother, she automatically corrected in her head. Something about that made her stop, though, although she wasn’t really sure why. She shook her head cursed Derek.

Even when he wasn’t there, she couldn’t get him out of her head. God, Derek really was a dick.

And now he had Casey cursing in her own head. She turned her attention back to the TV and tried to forget all about Derek fucking Venturi.

 

* * *

 

Casey didn’t see Derek again before she headed upstairs for bed. She had total control of the TV for a good three or four hours and she was able to have a dinner of carrot sticks, a sandwich on whole wheat bread, and white cheddar, reduced fat popcorn without dealing with Derek’s comments about animal food and whatever stupid things he thought were clever. She did all of this without seeing Derek again, and she only occasionally heard a lone bump from upstairs. Otherwise, it was like she was home alone, something that she definitely didn’t mind. She could get used to this.

By the time Casey headed upstairs, there was a bit of a pep to her step, even though she was definitely ready for bed. This night hadn’t gone according to plan, but it hadn’t been that bad either. She could get used to a Derek who spent his nights locked in his room.

She should have known that it was too good to last.

The storm had kept raging the entire time that she had been alone downstairs, and it hadn’t decided to stop just because she was ready to go to sleep. Casey was a bit surprised that it hadn’t tired itself out by now, and she was getting a little worried. Did storms normally last this long? Wasn’t this a sign of the coming apocalypse or something?

She was at the beginning of what would probably be an epic freak-out when her door suddenly creeped open. Casey shrieked and threw the closest thing she could grab at the door.

“Ow!” Derek yelled as he attempted to protect his head from Casey’s diary. It bounced off one of his arms and fell to the ground, a sound that Casey barely heard over the sound of the freak storm that was surely seconds away from tearing the house apart or starting an epic flood of biblical proportions. “What the hell was that for?”

“Why are you coming into my room in the middle of the night without warning me? This is all your fault!” Casey shot back as she grabbed one of her pillows and aimed for his head. Unfortunately, while she was quite a talented dancer, that did not extend to a good throwing arm, and the pillow ended up glancing off his side.

“That was really sad, Space Case,” Derek said as he picked up the pillow and fell onto her bed with it cushioning his head. “It’s like you’re trying to live the whole ‘girls can’t throw’ stereotype.”

“Shut up and answer the question,” Casey said while she tried unsuccessfully to pull the pillow out from under Derek’s head.

“Well, if you _must_ know,” Derek started as he turned to face Casey, his head still firmly on the pillow, “I was worried for your safety. After all, you’re the one in this house most prone to displays of unrestrained freaking out, so I thought I should check on you. I didn’t want you to come bother me while I’m trying to sleep.”

Casey narrowed her eyes. “So you decided to come bother me instead?”

“I’m being proactive – really, Case, you should be quite proud of me.”

“I’m slightly impressed that you know a word like ‘proactive,’ but otherwise, I call BS.”

“I’d be impressed if you actually said the word ‘bullshit’ instead of wimping out, but otherwise, I have no idea what you’re talking about.”

“Oh, don’t you?” Casey crossed her arms over her chest and leaned back against the headboard of her bed. “Fine, I call _bullshit_. Now tell me why you’re really here.”

Casey wasn’t quite sure how to classify the smile that had slipped onto Derek’s face. It was definitely a smirk, but not one of his normal ones. It looked a little smug, a pinch sly, and possibly even sneaky. It looked a little like the smile he wore when he found a new girl who was a bit of a challenge.

Casey shook her head slightly, trying to get that thought out of her head – where on earth had that thought even come from? Whenever Derek was around girls, he simply looked sleazy, not at all appealing.

Derek interrupted her worrying and spiraling thoughts. “Fine, I’m being a good stepbrother who thought his stepsister might be scared of the big, bad thunderstorm. Does that make you happy?”

Casey scoffed. “You’re not a good stepbrother – you’re never a good stepbrother. You’re not even a good brother to Edwin, let alone a good stepbrother to me.”

There was another crack of lightning that made Casey jump a little, but it made Derek practically fall off the bed. He managed to keep himself on the bed by grabbing onto Casey’s comforter. As soon as he righted himself, he shoved his head under the comforter, ending up somewhere around Casey’s feet.

Casey started to laugh, a big belly laugh that made her toes curl and not so accidentally kick Derek in the face. He came out from under her covers with a frown on his face. “Are you having some kind of breakdown?”

“You’re scared!” Casey managed to squeak out in between laughs and giggles. “Oh my god, you’re scared of the thunderstorm and you came into my room for comfort!”

Derek immediately started to shake his head. “No, no way, Derek Venturi is never scared. I told you, I’m the knight in shining armor in this situation.”

Casey tried rolling her eyes, but she was still too busy laughing to accomplish that. It took her a good minute or two before she finally stopped laughing.

Derek used that time to erase any fear from his face and just look totally emotionless and unimpressed, all at once. It really was an impressive feat, if Casey were in the habit of complimenting Derek, which she obviously wasn’t.

“Are you done?”

“Maybe,” Casey said with another giggle. “Ok, ok, now I’m done.”

“And, for your information, I am _not_ scared of something as silly as a thunderstorm. I just happen to pay attention in class every once in a while, and I know that lightning striking things is bad.”

“So?” Casey asked, trying to suppress a smile and failing.

“So, if a bolt of lightning hit the house, then we would be in trouble, and since this storm has been happening for fucking hours and lightning never strikes the same place twice, then the lightning has to be running out of places to hit. Our house is as good a target as any. So fine, I was a tad _concerned_ , if you’re going to beat the answer out of me.”

Derek ended his little speech with an attempt at looking smug, but more thunder took every ounce of pride out of his face right away.

Casey laughed. “Does Der-Bear need to sleep in my bed tonight?” She made sure to keep her voice as simpering as possible the whole sentence through.

“Well, if you’re going to _force_ me to stay in here - “

“Not doing anything of the sort,” Casey muttered.

“- then I suppose I should get comfortable,” Derek said happily as he crawled over to Casey and flipped the covers off her. “And, since you’re the host, then obviously you should give your blanket up for your guest.”

“Oh no you don’t!” Casey shrieked as she attempted to grab her blanket back. She was a little too slow, though, and he already had it tightly wrapped around him. “I am going to kick you out of here if you don’t give me back my comforter!”

“Well, if you’re going to be snippy about it,” Derek said with a laugh as he unwrapped himself. “Fine, but you need to scoot over – for such a little thing, you are taking up way too much room.”

“Oh, I’m sorry if I’m comfortable in my own bed,” Casey grouched as she pulled the blanket back over herself and moved over a few inches. It was her bed, after all – she was going to be the bigger person by letting the scared, frightened Derek stay with her, but she wasn’t going to let him take over her bed.

“Okay, before we go to bed, I think we should go over some rules,” Casey said as she shoved a pillow at Derek in an attempt to be a friendly host and possibly push him a few more inches away from her – it didn’t work, but it was a nice idea.

Derek groaned and used the pillow to hit his face a few times before shoving it under his head and completely wrecking its shape. It would take a while for Casey to get the Derek-ness out of it after this hell of a night. “Seriously, Case? We’re just sleeping in the same bed, I don’t think we need to turn this into something it isn’t.”

“Well, it’s my bed, so tough luck, Der-ek.” Casey made her point by jabbing her finger in Derek’s chest a few times. He grabbed the finger in a tight grip.

“Get off!” Casey tried to wrench her finger back, but Derek was holding onto it very tightly.

“No, if I’m going to have to sit through your rules, then you need to sit through some discomfort for a while,” Derek said while playing around with her finger, directing what was probably a terrible orchestra. He looked back up in her eyes. “Go on, let’s get this over with.”

Casey groaned but let him imitate an airplane in freefall. “Okay, Rule Number One is simple: respect my personal bubble. That means no shoving your feet in my face or taking up 75% of the bed. This is my bed and you’re a guest, so you get approximately 40% and the remaining 60% is mine and not up for any sort of invasion.”

Derek rolled his eyes but didn’t interrupt her for once.

“Number Two – don’t get used to this. I’m humoring you because I know that if I don’t let you stay here then you’re just going to keep me up all night.”

Derek raised his eyebrows. “And what would we be doing on this sleepless night?”

Casey narrowed her eyes. “I’m seconds away from pushing you out of this bed and doing a few jumping jacks on your f-ing head.”

Derek laughed. “You really need to get over your fear of cursing. It won’t actually send you to hell or make you head pop off or whatever you think is going to happen.”

Casey narrowed her eyes even further, even though it made it a little difficult to see Derek, and leaned in. “I will fucking hurt you. Are you happy?”

Derek laughed again. “Yeah, I’m good. Move on – what’s Rule Numero Tres?”

“This is the most important rule, so listen carefully.” Casey leaned in even closer, keeping her eyes on Derek’s. “We are never going to talk about this. Ever. No one is ever going to know about this.”

Derek chuckled. “You wish I would tell people about this.”

“Really, that’s the best response you have? God, you must be scared of this itty, bitty thunderstorm.”

Derek’s eyes got big. “Never speak of this again, you say? Sounds like a good idea to me!”

He quickly let go of her finger and flipped to his other side, his messy hair much too close to Casey’s face. She spit a stray lock out of her mouth before turning to face the window, trying to get as far away from Derek as possible.

This was going to be a long, long night.

 

* * *

 

Casey wasn’t sure how long it took her to fall asleep or how long she had actually been blissfully unaware of the world around her, but a particularly huge explosion of thunder broke her calm and sleep. For a few seconds, she was confused – she was in her room, which made sense, but something seemed different. It was still storming, but if anything, it would be odd if it wasn’t at this point. No, something else was different, something else was off, she just had to wake up enough to figure out what it was.

She went to rub her eyes, as if better eyesight could help her think easier, but she found that she couldn’t quite move one of her arms – it was being held down by an arm that was looped across her waist. At first thought, she figured it was Lizzie, sharing her bed because of the storm or something. Then she looked down at the arm and quickly decided that such a long, hairy arm probably wasn’t Lizzie’s. Then it all came rushing back, but it still didn’t make any sense.

Casey did her best to move her head enough to see Derek behind her. She should have known that Derek wouldn’t follow her rules, but she honestly thought he might last a little longer than a couple hours or however long it had been. He definitely wasn’t respecting Rule Number One – he was right up against her back, his breath ruffling her hair and making the back of her neck prickle with each warm brush of air. One arm was stuck in between his chest and her back, the other resting on her side and looped over her arm, resting on her stomach. His fingers would move every once in a while, jerking and dancing around from some unknown dream. She practically had to go cross-eyed to see it, but it looked like there was a small smile on his face.

Sleeping Derek was a good look on him, although Casey would never admit it.

The lightning was still flashing across the sky, the thunder creating a not-so-comforting soundtrack to the night. Derek frowned in his sleep, pushing closer to Casey’s back, his arm getting tighter around her waist. Casey let a gasp slip out, both from the sudden tightness and the unexpected contact.

Derek started murmuring under his breath, mostly gibberish that Casey couldn’t make out, but one familiar word slipped out – well, it wasn’t a word, but a name: “Casey.”

Casey wasn’t really sure what to do. She wasn’t thinking – that was really the only explanation she could think of for what she did next.

Casey slowly reached for Derek’s arm with the one free hand. She moved it enough that she could turn around, now facing him. They were too closer, but Casey didn’t get a chance to move back before Derek’s arm once again found its way to her waist, her hands now stuck in between their chests.

She could see the patchy growths of stubble that had cropped up over a long day and an even longer night. A freckle here and there, the odd scar from old acne marks. A little crinkle between his eyebrows, flickers of movement underneath his eyelids. She had never really seen Derek that close up – when they were actually near each other, invading each other’s personal space, it was normally because they were fighting, so she wasn’t exactly paying attention to details. She wasn’t really looking at him – she saw his stupid face every day, why would she need to pay attention to it?

But now she found herself cataloguing every detail. Casey wasn’t sure what she was going to do with all of this information, but she filed it away. That was something to figure out later.

Derek was fidgeting again, the one arm laced around her waist now attached to a hand that was twitching against her back. The furrow in between his eyebrows was deeper, a frown on his face. The thunder was roaring and the storm was raging and Derek was afraid, so Casey couldn’t help herself – she reached up, putting one hand on his chest and the other on his lips. She started to sing a song, some old nursery rhyme her mother sang to her when she was little and that they both sang to Lizzie.

It seemed to work, seemed to calm Derek down, but it didn’t soothe him back to sleep – it brought him out of his troubled slumber. As soon as she saw his eyelids flickering, Casey knew she should back off, that she should lower her hands or stop singing or at the very least put another inch or two between them, but she didn’t. She stayed there, her eyes looking into his sleepy ones.

“Case?” His voice was weak and groggy. “Whaz – what’s going on?”

“Shh,” Casey murmured. “You’re fine.”

Derek gave her a sleepy but beautiful smile. “Of course I’m fine, I’m with you.”

Casey laughed. “I think you’re a little too tired to be thinking clearly right now.”

“Maybe, but I still know it’s you, Casey McDonald.”

Casey wasn’t sure how to respond. She wasn’t even sure that she was awake – maybe she was actually asleep, and this was a dream, although she wasn’t sure why she would want to dream about this.

“Just go back to sleep, Derek Venturi.”

This must be a dream – Derek merely smiled and did exactly what she said. He didn’t argue, he didn’t make some dirty joke, he didn’t try to annoy her. He just fell softly back into sleep with a smile on his face.

Casey was glad that he was the first one to fall asleep – it meant that he didn’t notice the smile that was on her own face as sleep slowly took over her mind.

She had one final thought, before sleep happened – or more sleep, if she was in fact still asleep during this odd little episode: the first rule was obviously shot, had been soon after she had laid it down; the second rule might be on its way to being broken, depending on what happened in the morning; but there was one thing that was very clear to Casey – no one would ever know about this. Rule Number Three would never be broken, even if they managed to obliterate every other rule she could come up with.


End file.
